1. n. [Geophysics]
An elastic body wave or sound wave in which particles oscillate in the direction the wave propagates. P-waves are the waves studied in conventional seismic data. P-waves incident on an interface at other than normal incidence can produce reflected and transmitted S-waves, in that case known as converted waves.
Synonyms: dilatational wave
See: body wave, dilatation, elastic, rarefaction, shadow zone, wave